Operations for recovering and transporting viscous hydrocarbons such as crude oil, bitumen and processed or semi-processed refinery products are faced with challenges in terms of high viscosity and high pressure drop due to fluid mechanic phenomena. Friction between the viscous fluid and the wall creates frictional pressure drop, i.e., drag, which reduces performance and flow in such operations. Increasing pumping power counteracts drag, but is disadvantageous because it requires larger pumping stations, expensive pumps, and adds energy costs.
Drag reduction is the increase in pumpability of a fluid and can be effected by the addition of a drag reducing additive to the fluid. At present, polymers are used as drag-reducing agents. For example, water-soluble long-chain hydrocarbon polymers have been effective in reducing horsepower requirements and/or increasing injection rates during treatments. Drag reducing additives used commercially are aqueous suspensions of polymers.
However, drag reduction has not been effectively implemented in the pipelining of large quantities of viscous hydrocarbons, such as crude oil, bitumen, kerogen, asphaltene, or tar. Notably, heavy crude oil has been a challenge for existing commercially available drag reducing agents.
Drag reducers that are currently being used by the oil industry have disadvantages because, during pipeline operations, the long-chain drag-reducing polymers easily degrade due to shear forces. This degradation reduces the efficiency of the pipeline and increases costs. In order to replace the degraded drag reducers, a fresh drag reducing agent must be added frequently in various sections of pipelines, such as pumping stations. Accordingly, there is a need for new, more stable, and improved drag reduction methods and compositions.